Electronically read credit cards may be targeted for theft and misuse. Readily available card readers can be used by a thief to obtain account information from the card. While magnetic strip and contact-bearing cards are protected to some extent by the fact that the card must be in physical contact with the reader, contactless cards that use radio signaling to exchange information with a host system can be used without bringing it into direct contact with a reader. Because such contactless devices can be read at a distance with a suitable transmitter and receiver, it is possible to surreptitiously obtain information from the card while it remains in its cardholder's possession. In addition to non-contact data transfer, wireless communication can also allow non-line-of-sight communication, meaning that an RF-enabled device may be read while it remains in the cardholder's wallet or purse.
U.S. Pat. No. 6,863,220 issued to Edwin J. Selker describes contactless information storage devices, such as an RFID payment cards, that are protected against unauthorized misuse. The card employs an internal mechanism that normally disables the on-card electronic circuitry until the mechanism is intentionally actuated by the cardholder. The mechanism prevents the information on the card from being accessed until the cardholder activates the mechanism to enable signal transmission between the card and the remote unit. In one embodiment, user- activated, normally open electrical switch contacts connect the on- card electronic circuitry and an on- card antenna. Until the contacts are intentionally closed by the cardholder, the antenna is disconnected to prevent the card from transmitting or receiving information. After the user intentionally closes the switch contacts when the card is being used to provide information to an authorized remote reader/transmitter, the contacts automatically reopen to prevent the card from being accessed. In an alternate embodiment, a mating key in the possession of the cardholder must be brought into proximity with the card to close the normally open switch in the card to permit information to be read from the card.
As further described in U.S. Pat. No. 6,863,220 and in the specification that follows, the on- card switching mechanisms described above may be used to selectively connect the chip electronics to different portions of the on-card antenna, allowing the card to he selectively tuned to different resonant frequencies. The card may be pressed in different positions to activate different switching elements, and different keys, or different placements of a single key, may be used to selectively close only certain on-card switches to provide the needed connections.
These on-card, cardholder-operated switching devices provide a needed mechanism that enables the cardholder to input additional identification or control information that provides additional security and functionality.
The internal mechanism used to generate data in response to the selective manipulation of the card by the cardholder must be flat enough to fit in the limited space available in a card meeting relevant ISO standards, must be robust enough to withstand stress and abuse, and must employ low-cost components and be easy to assemble and produce in quantity. In addition, the mechanism must not be potentially harmful to users due by introducing sharp or pointed edges, leak fluids, or contain a substance that might trigger allergic reactions. In addition, the mechanism employed should be functionally flexible in order to work in cards and other devices having a variety of shapes and sizes. Finally, the mechanism should be able to control the on-card electronics, typically a mass-produced integrated circuit chip, regardless of whether the chip is internally or externally powered.